crg53

I am in the process of installing relays for my head lights; was going with Daniel Stern's kit, but he seems to be missing in action. So my question is: do I need relays with diodes, or can I use regular ones? What does the diodes do?

Thanks in advance.

darth

If the diodes are across the coils they are refered to as clamping diodes and are there to protect electronic components which are controlling the relay from the high voltage generated (i.e. by the collapsing magnetic field) when the coil current is shut off . If there are no electronics driving the relays you don't need the the relays with diodes.

crg53

Thanks Darth. Do you know if that is the case with the 964's headlights?
As far as I can see, the head lights are only manually switched, not electronicly driven.

Rocket Rob

I installed relays recently for my upgraded H4s. No diodes were required. I used Daniel's wiring kit and schematic.

No affiliations, just a happy customer.

crg53

Thanks Rob, I was going with Daniel kit myself, emailed him several times in the last 2 weeks, but no reply; maybe he on holidays.

campoj2

What relays do you need for H4s??

darth

Can't say for sure, not knowing what's in the box labeled "Beam select or switch" from the schematic.

crg53

I ordered my relays through www.rallylights.com and the parts # is HL 87118; these are Hella 40amp relays with dual 87 post, which mean there are 2 posts out, one for each headlight; you will need 2 relays, one high beam, one low beam. No affiliation..................... You will also need light sockets for the bulbs with a minimum of 14 gauge wire.
These dual 87 relays are hard to find, spend hours on the internet.
For schematics, go to Daniel Stern website, or search Rallylights website for wiring info.

campoj2

I'm guessing that the they are not direct plug and play to what is in there now?

If I'm running stock bulbs do I need to get these relays???

crg53

When I went to H4 lights I did not notice a great improvement, that is why I am now installing relays. Please read Daniel Sterns article on relays, very informative; he can answer all your questions way better than I can.

Rocket Rob

In the US, 964's came with H5's. If you are switching to H4s, you need to change the plugs to fit the H4 style connector.


No, if you are planning on running the stock wattage bulbs (55W low, 60W high). However, on of the benefits of the H4's is that there are a lot of optional high wattage bulbs available. I am running 80W low and 100W high. If you run the higher wattage bulbs, relays are recommended. The Porsche factory wiring runs the full current of the headlights through the headlight switch. You risk melting/damaging it without relays with the extra current.

campoj2

I have the connector to do the switch.

Now I understand the issue about the bulbs & relays and higher current that they can run,.

I'm assuming when I call Mr. Sterns' office and tell them that I am swapping out 964 H5s for H4s they'll know what I am talking about and be able to guide me down the right road?? Any words of wisdom would be helpful.

Thanks,
John